"Our laboratory is elucidating the nature of the immune response to murine tumors and establishing principles which may enhance our ability to immunize patients against known tumor antigens. We have used therapeutic cytotoxic T-lymphocyte lines to identify tyrosinase-related protein 2 (TRP-2) as a tumor T-cell-antigen from the B16 melanoma by immuno-screening a cDNA library from this tumor. In a parallel system, we also found that the transmembrane component of a retroviral envelope protein, encoded by a C57BL/6 germline gene was a tumor-associated T-cell antigen for a large number of murine tumors of different histologies (colon adenocarcinoma, fibrosarcoma and melanoma). For each of these tumor antigen models, we have also defined the minimal determinant peptide recognized and used it to generate CTL which were therapeutic for the parental tumor in vivo in adoptive cellular transfer experiments. Subsequent studies defined the nature of the CTL responses to these minimal determinants in naive and tumor-immune animals and described CTL avidity for the peptide-MHC complex as the prime discriminant of anti-tumor immunity in these systems. Experiments showed that in vitro stimulating peptide concentrations modulated the avidity of the CTL generated and that range of CTL avidities in tumor-immunized mice was higher than in naive and other non-immune mice. Continuing work on murine pre-clinical tumor antigen models has also identified murine Cathepsin L (also described as Major Excreted Protein [MEP] and mouse cysteine proteinase), a protein highly upregulated by transformation by ras, as a tumor-antigen recognized by a T-cell clone reactive with the MC38 murine colon carcinoma. Epitope identification studies and vaccination experiments with this new antigen are underway. In other studies, we have developed methodologies for identifying tumor-specific CTL from patients with renal cell cancer and using the techniques described above to identify tumor-associated T-cell antigens in this tumor. Recently we have generated MHC-restricted cytotoxic T-lymphocytes clones from patients with renal cell cancer (RCC) which react with their autologous tumor. Using one of these CTL clones (HLA-A3 restricted), we then screened a tumor cDNA library and identified a renal cancer gene that encodes a recognized antigen. This proved to be a member of the fibroblast growth factor (FGF) family with known transforming activity. It also appeared to retain the unmutated germline FGF sequence found in the patient's PBL and therefore may represent a tumor antigen target that may apply to other renal and non-renal cancers which over express this gene. In addition to the above work, clinical studies investigating the optimal IL-2 regimen for inducing the regression of advanced renal cell cancer are also ongoing. A prospective randomized 3-arm trial comparing subcutaneous IL-2 versus high and low- dose intravenous IL-2 in the treatment of metastatic renal cell cancer is nearing its full accrual of 350 patients. This represents the only study to address the most effective way to administer IL-2, which is likely to be an important component of any combination immunotherapy strategy for advanced RCC."